Modelling/Creating the Rigid Body

Even though not 100% appropriate on this structure, as an example, we with to make a regularised rigid body of this 5 membered with with equal bond length and angles.

Warning: more detailed and more powerful options are giving in the Crystals Manual

http://www.xtl.ox.ac.uk/crystalsmanual-6.html

To Regularize the ring

#regu replace
group 5 
target        {click on the 5 atoms of the ring using the mouse - or type them in}

cp-ring 1.4     (1.4  Angstrom is the idealised bond length for the ring in this 
                    example - the default if nothing is entered is 1.4 Angstrom)
end

Refining selected atoms as a rigid body

If you already have directives in the list12 (parameter definition list), you would have to edit the list12 via the Refinement, Edit Directives menu option.

Following is the simplified version using the GUI which will create a brand new List12:

#list 12        (space between the "#list" and "12")
block x's      (refine positions of all atoms)
group {click on the 5 atoms of the ring using the mouse - or type them in}
end